Fluorenylidene-xanthene and related polycyclic systems are typical examples of bistricyclic aromatic enes (BAEs); however, polycyclic systems of fluorenylidene-xanthene are relatively scarce. Here we synthesized a series of novel ladder-type polycyclic systems containing fluorenylidene-xanthene units, differing from the classic Barton’s two-fold extrusion reaction. In the new synthetic scheme, the very popular Suzuki reaction was first used to couple the corresponding precursors, then a catalyst-free nucleophilic aromatic substitution reaction between Ar–F and Ar–OH groups in the backbone afforded ladder-type O-heteroarenes. Moreover, the new synthetic strategy is also suitable for the synthesis of other heterocyclic and polycyclic aromatic hydrocarbons. Some of these products showed reversible mechanochromism properties.

中文翻译：

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通过亲核芳香族取代反应合成规则梯形芴基-氧杂蒽低聚物


芴基-氧杂蒽和相关的多环体系是双三环芳香烯 （BAE） 的典型例子;然而，芴基-氧杂蒽的多环系统相对稀缺。在这里，我们合成了一系列包含芴基-氧杂蒽单元的新型梯形多环系统，与经典的 Barton 二重挤压反应不同。在新的合成方案中，非常流行的 Suzuki 反应首先用于偶联相应的前驱体，然后在主链中的 Ar-F 和 Ar-OH 基团之间进行无催化剂的亲核芳香族取代反应，得到梯形 O-杂芳烃。此外，新的合成策略也适用于其他杂环和多环芳烃的合成。其中一些产品显示出可逆的机械变色特性。